Infrared LED (light emitting diode) with light emitting wavelengths in the infrared region (700 to 1500 nm) is widely used for photocouplers, light sources of remote controllers, and other infrared communications.
Among such infrared LED, ones using Ga1−xAlxAs-based compound semiconductors or GaAs-based compound semiconductors etc. are known (for example, see Patent Document 1).